I performed a de-novo assembly of PacBio reads using Canu for a viral genome. I have my resulting unitig from the canu pipeline. I am now interested in characterizing repeats in my resulting assembly. I'm new to assembly and repeat identification. One simple approach was taking the reads used to form the assembly, align them against the assembly with MUMmer, and take a look at the resulting dot plot? Are there any more sophisticated approaches that would yield better results?

Yes, you should probably try RepeatModeler, which can detect repeat families (de novo) and classify them. It has worked well for both model/non-model species and is very easy to run (it does have few dependencies to install though: TRF, RECON, RepeatScount, NSEG).